Sponges
Sponges are often seen in the ocean, but did you know they also are found in healthy lakes?
Greenish spongy-looking clumps attached to submerged sticks and plant stems in clear, well-oxygenated lakes are freshwater sponges. There are 150 species of freshwater sponges, which are members of the animal kingdom but are often mistaken for aquatic plants or algae. Most sponges are green, because algae is living in their tissues. Freshwater sponges vary in size from a less than an inch to three feet.
They are most commonly seen in summer or fall, and may appear sporadically often being abundant in a lake one year and absent the following year. Sponges are usually finger-shaped, and can be soft or hard. Their casings make the species strong enough to be picked up without falling apart, unlike many kinds of algae. So, next summer study some nearby lakes for one of many species that survives in both ocean and freshwater envrionments.
December 22, 2005 6:29 AM | Category: Animals